“Collectors of cinema memorabilia have a name for anonymous actors who were photographed for publicity stills, but never actually made a film," says John Stezaker. “They call them 'virgins'. When I go to collectors' fairs, it's the virgins I'm after. There is a certain melancholy attached to the faces of actors that did not make it and to images that were destined to disappear. I'm very drawn to that.”

A large desk in the back room of Stezaker's house in north London is cluttered with photographs of “virgins”, some of which have been sliced in half diagonally or carefully cut around so that only a silhouette of the face remains. These black and white portraits of anonymous failed actors, found at fairs, flea markets and online, are one of the key sources of raw material for Stezaker's art. He collects photographs in order to deface them and, in the process, create something new and arresting.

“I'm using an archive to create another archive of my own,” he elaborates. “My ideal is to do very little to the images, maybe just one cut: the smallest change or the most minimal mutilation. What I do is destructive, but also an act of deliberate passivity.”

Stezaker has been quietly making his photographic collages for 40 years, but recently the art world, led by Charles Saatchi, who began collecting his work in the mid-noughties, has “discovered” him. As a result, he has only recently given up his day job teaching critical and historical studies at the Royal College of Art in London. “I am finally being embraced by an art world that, for a long time, I consciously kept at arm’s length,” he says, smiling, “And, at an age when most people are thinking of retirement, I suddenly find myself able for the first time to make a living exclusively from my art.”

“I have always thought the world would catch up with me one day, but perhaps not in my lifetime,” he says, smiling, “It has been a bit overwhelming. I actually fell ill last year with pneumonia and I do think it was to so with the stress of sudden success. I was saying yes to every show, every opening, ever invitation to lecture. I've stopped doing that now now, though I will be going to Sydney for the Biennial as it's quite a big deal to represent Britain there.”

Soft-spoken and thoughtful, Stezaker graduated from the Slade school of art in 1973, having gave up painting for film in his first year. “I had a big TV in my bedroom and a camera set up to shoot old B-movies that were shown late at night on BBC2,” he elaborates. One film that resulted featured a series of found images of people approaching windows, all taken from old Hollywood films. He showed it on a carousel slide projector with no sound. He has recently returned to film, having bought a huge photo archive from a music agency that was closing down. “It's mainly press and publicity pictures of long-forgotten female trios and male duos. I'm making a film in which they are pictured singing, but you do not hear anything. I'm fascinated by the application of silence and how it creates a spectral world. For me, it's a way of showing the sovereignty of image over sound.”

For now, though, it is his photographic collages that have belatedly made John Stezaker's name in a global art market that, in these more restrained times, is in retreat from the recent excesses of conceptualism. “I've always made a distinction between collage and photomontage,” he says. “Montage is about producing something seamless and legible, whereas collage is about interrupting the seam and making something illegible.”

Over the years, he has become a master of slicing and splicing, often, as in the Marriage series, juxtaposing two vertically or diagonally cut faces – one male, the other female - to create a single often-surreal portrait that both exaggerates, and subverts, our received notions of glamour, personality, gender and celebrity. “There is something very odd, even unnerving about cutting through a photograph,” he says. “It sometimes feels like I am cutting though flesh.”

Sometimes, too, by simply placing an old hand-coloured postcard of a landscape across a face he creates a strange new world where the romantic pictorial tradition meets surrealist iconoclasm. The end results are always both deceptively simple in their execution and oddly disturbing in their suggestion. “When we look at a face, we assume that we are looking behind the face for a personality,” he says, “By making literal that behindness, I often create something that twists into an image of horror. It often takes me by surprise, because it is not what I have set out to do.” To this end, his work often evokes literary as well as visual precursors and he namechecks Kafka, Mallarmé and Bataille alongside Jasper Johns and “the stranger side of the English romantic tradition”.

For a long time he worked long into the night fuelled by strong coffee. “In the early hours, through tiredness, the unconscious takes over and that is when the real creativity happens.” Since his illness, though, he has had to adjust to normal working hours. “When I'm deep into my work, it's like my alter-ego takes over and all I am doing is witnessing the creativity,” he says, smiling. “That's what I love about what I do. I am nearly always the viewer; I'm only a producer at the moment of the flash of the knife.”